1. Field of the Invention
The present invention relates to a bearing device for a diagnostic radiography system of the type having a support plate with a portion for accepting a first region of an examination subject and a support element for a second region of the subject, the support element being connected to the support plate such that it can be adjusted by an adjusting mechanism.
2. Description of the Prior Art
Support devices such as this are used in computed tomography (CT) systems, for example, where they serve for accepting human patients. There, the portion of the support plate that is provided for supporting the first region of the examination subject is designed as a support for the body of the patient, and the support element is designed as a head support. To guarantee the adjustability of the head support relative to the support plate, the two parts are connected by a hinge, which can be locked when the desired incline has been set. Since the hinge is under heavy load, it must be produced from materials that are very sturdy and thus very dense. This leads not only to artefacts in the tomograms, which are generated by means of the CT system, of a patient reclining on the support plate, but also to disturbances in shadow images, known as topograms, which are commonly prepared prior to the actual computed tomography process in order to be able to localize an area of the patient of which to generate the tomograms. The imaging of the hinge in such a shadow image can render it unusable.
The risk of the occurrence of artefacts in the shadow images or the occurrence of superposed attenuation in the X-ray images, can be reduced by mechanical constructions utilizing expensive plastics, however, this solution is not satisfactory to medical personnel. Also, the lack of adjustability of the head support relative to the support plate is seen as unacceptable by medical workers.
An object of the present invention is to design a support device of the type described above wherein the adjustability of the support relative to the support plate is guaranteed without a consequent reduction of the diagnostic value of the X-ray images that are generated from an examination subject who is located on the support plate.
This object is inventively achieved in a support device for a diagnostic radiography system which has a support plate with a portion for supporting a first region of an examination subject and a support element for a second region of the subject, wherein the support is connected to the support plate such that it can be adjusted by an adjusting mechanism which is arranged on the side of the support faces away from the section of the support plate which is provided for accepting the first region of the examination subject.
In contrast to conventional devices, the adjusting mechanism in the inventive device is not located between the section of the support plate that is provided for supporting the first region of the subject and the support element for the second region of the subject; rather, it is arranged on the other side of the support element, and thus on the other side of the second region of the subject, as seen from the section of the support plate that serves for supporting the first region of the subject. It is thus clear that, as a rule, it is not possible for an image of the adjusting mechanism to be superimposed in an image of an examination subject, nor for it to cause artefacts in tomographic imaging of the subject.
The adjusting mechanism, by means of which the support is preferably attached to the support plate such that it can be swivelled about an axis extending essentially transverse to the longitudinal axis of the support plate, can be attached to the support plate permanently or detachably according to different variants of the invention. In the case of a detachable attachment of the adjusting mechanism, a screw connection can be provided, though a plug connection may be advantageous for more comfortable handling.
According to variants of the invention, to guarantee adjustability of the support relative to the support plate, the adjusting mechanism can have an articulated joint for adjusting the angle of the support element relative to the support plate and/or an arrangement for adjusting the height of the support element relative to the support plate. In a preferred embodiment of the invention,a push-pivot joint is provided, which can be displaced on a carrier extending essentially perpendicular to the support plate for height adjustment and which connects the support to the carrier in a pivoting manner for adjustment of the inclination.
In the case where the support device is provided for a patient, the section of the support plate that is provided for supporting the first region of the examination subject is fashioned as a support for the body of the patient, and the support element is fashioned as a head support
The inventive bearing mechanism is preferably provided for a CT system.